I was about to use gRPC, but forget that non-browser-supporting non-human-readable dumpster fire.<p>Also it looks significantly less complicated than open api/swagger. for starters, openapi/swagger has 2 fkin names. lol.
You can play around with OpenRPC in the API documentation viewer and editor here: <a href="https://playground.open-rpc.org/" rel="nofollow">https://playground.open-rpc.org/</a>